Refrigerator and control mechanism therefor



May 13, 1952 G. A. BRACE REFRIGERATOR AND CONTROL. MECHANISM THEREFOR Filed Jan. 21, 1948 2 SHEETSSHEET l EMU- I N VEN TOR. George A. Brace Fig.1

y 1952 G. A. BRACE 2,596,523

REFRIGERATOR AND CONTROL MECHANISM THEREFOR :9 1 V///////////////////////// ix\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ l Fig. 3 INVENTOH. 060298 A. Brace ATTORNEY.

Patented May 13, 1952 UNITED STATE- S PAT ENT OFFICE corporation of Ohio Apnea-an January 21, rats, iseiaino. 2,472;

14 'Glaims. 1

The present invention relates to refrigerating apparatuses and more particularly to a Terrie-er ating apparatus of the dual intermittentabs'orp tion type and the mechanism for governing the operation thereof.

It is an object of'the present inventiontoprovide a control mechanism for an "intermittent absorption refrigerating system which Exercises all its control functions through the operation of a pilot valve.

It is a further object of the present invention to provide a control mechanism for an intermittent absorption refrigerating system which normally cycles the apparatus to produce refrigeration and which holds the apparatus in a nfon- Y paratus to the condition obtained prior to 'i'n- 5 tervention of the manually operative 'rn'ea'ns.

It is a further object of the present invention to provide a refrigeration control mechanism which simultaneously regulates the "operation of the refrigerating mechanism and the efficacy or '11- heat transfer conditions within the refrigerating chamber.

Other objects and advantages or the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which: 4

Figure 1 is a schematic view illustrating the present invention; i

Figure 2 is a view partly in section and partly diagrammatic illustrating the control mechanism forming the subject matter of the present invention; and V Figure 3 is a detailed view of part of the mechanism of Figure 2.

The refrigerating mechanism per se consists of two identical units of the intermittent absorption type. Only the left hand unitof Figure 1 will be described specifically. The right hand unit of Figure 1 is identical with the .left hand unit, hence correspondingparts are provided with corresponding reference characters distinguished sarily, of the type which contains a dry-salt jab'sorbentfsucfh as strontium chloride, for a refrigerant, such as ammonia. The generatorabsorber his made up of three concentric chambers. The central chamber 11 is a products of combustion flue which is surrounded by an annular cooling jacket Ill. An annular chamber [2 surrounds the cooling jacket In and constitutes -the housing for the absorbing materia1. The absorbing material contained in the space l2 communicates with the condenser C through the 'fcbifd'uit '13. The cohdenserC communicates with -the lviaporator structure E by a conduit M. The condenser C comprises a plurality of finned tubes in which the refrigerant vapor is condensed. The heat of condensation of the refrigerant is rejected to cooling air flowing over the condenser tubes.

The evaporator E comprises a liquid receiving chamber [5 "which receives refrigerant in the first instance from the condenser discharge conmin [4. The heat absorbing surfaces of the evaporator comprise a pair of vertically extendingsinuous conduits l6 and fl which receive refrigerant liquid in common from the liquid receiver 45 by way of the conduit [8 and open at their u l p f ends into the upper portion of the reservoir 15. The evaporator conduit [6 is an air cooling conduit and, as shown in Figure 2, is provided with air cooling fins 20.

Aconduit 23 eonnects the upper portion of the cooling jacket Ill with a finned tubular aircooled condenser 22-. This .portion of the system is charged with a cooling medium such as methyl chloride. Cooling-medium vapor condensed in the condenser Z2 discharges into the reservoir 24. Cooling liquid is then conveyed from the reservoir 24 to -the upper portion of the jacket 10 by a conduit 25. The conduit 25 comprises an upwardly facing U-shaped portion 26, a downwardly facing U-shaped portion 21, and an upwardly facing U-shaped portion -28 which connee-ts to the upper portion of the cooling jacket 40. Thereservoirs 24-44" are interconnected by a gas conduit 28 which joins the reservoirs above the level at which the condenser discharge conduits 3l 3U terminate therein.

The bight portion of the downwardly facing ll -shaped conduit section 21 is thermally bonded to a metallic bar 32 of high conductivity which extends through the entire length of the products of combustion flue 'II and terminates shortly therebene'ath. The conduit 21 is not in the path of the products "of combustion discharging from the'ilue lfijbutti's positioned laterally to one side thereof. This conduit receives heat through the conducting element 32 which is normally heated simultaneously with the generator-absorber A in a manner to be described more fully hereinafter.

When heat is supplied to the generator-absorber A, heat is conducted by the element 32 to the conduit 21 to vaporize a portion of the cooling medium. Vapor formed in conduit section 21 fills the horizontal section of the conduit and a part of the downwardly extending legs thereof so as to form a vapor lock to prevent further flow of cooling medium from the reservoir 24 into the cooling jacket Ill.

As shown in Figure 1, during the period of time when the vapor lock is operative to prevent circulation, liquid accumulates in the reservoir 24 to a depth suflicient to submerge the end of the conduit 30. If heat is applied to the generator-absorber A, for example, under the conditions illustrated in Figure 1, and the application of heat to the generator-absorber A is discontinued there will be a sudden increase in pressure in the cooling system associated with the generator-absorber A which will be applied through the conduit 29 to the surface of the liquid in the reservoir 24. Due to the sealed condition of the lower end of the conduit 36 this will, apply an excess pressure on one side of the vapor lock suflicient to unbalance the same and to cause it to collapse with great rapidity. This subject matter is described and claimed in the copending application of Curtis C. Coons, Serial Number 692,267, filed August 22, 1946, now Patent No. 2,513,148, dated June The generator-absorber A is heated by a combustible fuel burner, such as a gas burner, 40 positioned beneath the generator-absorber to discharge its products of combustion into the flue II. An auxiliary gas burner 4| is positioned beneath the projectiong end of the conducting element 32 to apply its flame directly onto this element for a purpose to be described hereinafter. The burners 40-40 and 4|-4|' are arranged to be ignited by a flash tube pilot structure indicatedgenerally at 43.

As shown in Figure 1, the gas supply conduit 45 supplies fuel to the flasher pilot through the by-pass conduit 46 and to a gas valve control housing 41.

Referring now to Figures 2 and 3, the control mechanism is developed in detail. The housing 41 is interiorly divided into three chambers 50,

| and 52. The supply conduit 45 opens into 56--56' urge the valve plugs 54--54' onto their seats. The flexible diaphragms are provided with restricted bleed ports 5151' to admit gas from chamber 50 to chambers 5| and 52. The top of the housing 41 is formed as a pilot valve casing 59 which receives a slidable valve control element 60 provided with a single port 6|.

The top wall of the chamber, 52 is provided with a discharge port 63 controlled by the slide valve plate 60 and communicates with a gas conduit 64 which, as shown in Figure 1, terminates adjacent the main burner 40. The left hand side of the casing 50, as viewed in Figure 2, is provided with a port 65 also controlled by the valve plate 60 which communicates with a gas conduit 66' which supplies gas to the burner 4|. The right hand end of the chamber 50 is provided with a port 51 communicating with a gas conduit 66 which supplies gas to the burner 4|. The chamber 5| is provided with a port 68 communicating with a gas conduit 64' which terminates adjacent to the main burner 49.

The valve structure 53-54 controls communication between chamber 50 and a gas conduit Iii-which supplies gas to the burner 40. Similarly the valve structure 5354' controls communication between the chamber 50 and the conduit 1| which supplies gas to the burner The pilot valve plate 60, shown in its extreme left hand position in Figure 2, extends beyond the housing 41 and terminates in an enlarged portion having a pin and slot connection 12 with a pivoted snap acting control lever 13 which is imder the bias of a tension spring 14.

The arc of movement of the snap acting lever 13 is limited by the adjustable stops 16 which are carried by a control plate structure 11.

The lever 13 is actuated by a pair of pivotally mounted snap acting links ,1818 respectively which are connected by a link 19 for simultaneous operation. The linkage 1818' isactuated by a spring 80 which is appreciably stronger than the snap spring 14 which operates the lever 13. The links 18-18 are arranged to be actuated by the opposed thermostat bellows 8|-8| respectively. The bellows 8|-8| have their actuating bulbs 82-82 in contact with the absorber-generators A-A' respectively.

In the position of the apparatus illustrated in Figure 2 the bellows BI is expanded to its full extent and has just operated the snap acting mechanism to the position shown thus shifting the opening 6| in the plate 60 into position to provide communication between the port 63 and conduit 54 to vent gas from the chamber 52 without resistance through the conduit 64 adjacent the burner 40. When chamber 52 is vented the excess gas pressure on'the side of th diaphragm 55 facing chamber 50 overcomes the resistance of spring 56 and opens the valve port 5354 allowing gas to fiow'through the conduit 10 to the burner 40 for heating the generator-absorber A. The bleed passageway 51 in the diaphragm 55 is so small that it allows only a very small quantity of gas to pass therethroughper unit of time, consequently a pressure differential in the chamber 50 is maintained overand above that prevailing in the chamber 52 by reason of the resistance to gas flow through the valve 54-53 and the usual spud or jet associated with the burner 48. By this construction the valve 53 -54 is maintained in, open condition as long as gas is allowed to vent freely from chamber 52 through the conduit 64. 'Gas discharged through conduit 64 is consumed in the flame of the burner 40. I

As th generator-absorber A gradually heats, it eventually reaches some predetermined end point temperature at which the bellows 8| will expand to the right as viewed in Figure 2. As'the bellows expands :it will actuate the snap acting mechanism 18-18 over center against the bias of spring 80. As this mechanism snaps over center the lever 18 will strike the snap acting lever 13 and actuate the same to its extreme right hand .position as viewed in Figure 2. This operation will shift the valve plate 611 to seal thecha'mber 52 and to a-llow the chamber iil to went. Assoon as chamber 52 is sealed the gas pressure in chambers 59 and 52 will quiclcly equalize through the bleed passageway 51 and the valveSS-fl will close thus de-energizing the burner 40. The chamber "51 is now allowed to vent which will-open the valve 53-53 thus supplying gas through conduit H to the heater 40' for the generatorabsorber A. i

The limits of movement or the snap acting mechanism 18 -l'8' are determined by the fixed stops 83 and 83'.

The foregoing alternate operation of the control mechanism continues so long as there is a demand for refrigeration alternately heating and cooling the generator-absorbers "soon as heat is applied 'to either generator-absorber heat conducted from the products of combustion discharged by the burners 4D 'or 50 quickly activates the vapor lock 21-01- 21 associated with the generator-absorber being heated to interrupt *and prevent further iiow of the cooling medium into the cooling jacket-of such generator-absorber.

Th evaporator structure is positioned in the upper central portion of the cooling chamber of the cabinet with the inner section IT-H or the evaporator positioned within an insulated housing structure 86 to refrigerate the same and its contents. their associated fins 20-29 respectively are positioned laterally on opposite sides of the-housing '86. An air directing casing 81 houses the entire evaporator structure to form air flues over the evaporator sections iii-16} and their associated fins. The bottom portion 'of casing 81 is slightly constricted as shown at 88 and air inlets are provided at '89 in the upper portion thereof so that air from the cabinet may enter through the openings "89, flow downwardly over the iins 2il2il' and exit into the general food storage compartment through the constricted portion 88 of the housing '81. A plurality of air flow control valve plates 90 are pivotally mounted in the constricted throat 8-8 of the housing 81. The pivot pins of valve plates 90 are providedwith actuating cranks 9| engaged in slots in a drive link 92 which is slidably mounted by any suitable means, not shown, on the housing 81. The drive link 92 is provided with a downwardly extending plate 93 which is urged to the left, as viewed in Figure 2, by a compression spring 94 against a thermostatic bellows 95. The bulb 9 B of the bellows 95 is positioned in contact with one wall of the housing 87 in the path of the air stream rising upwardly in the food storage compartment so that the same responds to the temperature conditions obtaining in the food storage compartment of the refrigerator. The arrangement is such that expansion of the bellows 95 against the force of the spring 94 indicating a demand for refrigeration, moves the valve plates '90 into the full open position to allow maximum air flow across the air cooling evaporator structure Iii-46. When the air with-in the food storage compartment reaches a predetermined temperature such as 35 or 3 8 F. the bellows collapses and the bar 92 is advanced to the left as viewed in Figure 2 under the bias of spring 94 to move the plates 99 to the full closed position. By reasonoi this construction substantially uniform temperatures are maintained within the food storage compartment of the refrigerator withoutthe risk of freezing the same and without placing limitations upon the lowest temperatures which may The evaporator sections 6---|6-' and 6 be a0hieved within the insulated compartment '86.

The control plate element '11 slidabiy receives a U -shaped member 98 which is provided with downwardly extending stop lu'gs 99 and 99', These stop lugs are biased by torsion springs into the downward position shown but are so mounted that they may swing inwardly toward each other against the bias of the torsion-springs. The 'U -shaped member 98 is urged downwardly by a tension spring 190. when the member 98 is in its lowest-position the elements '99 :and 99" are in the pathof movement oi the -snap link 13. If, 'forrexarn-ple, the snap link 1-3 is actuated from the position "shown toward the right while the element 98 is in its lowest posi'tion it will ride by the lug 9!) but will be brought to a dead stop by the lug element 98 Thus the arm 13, under the conditions assumed will be brought to a stop in the dotted line position designated d. In position of the apparatus the slide plate 60 will have aligned the port '61 with the port 6 and conduit '66 which 'w-illsupp'ly gas through the pipe to the auxiliary burner M. This burner will maintain the heat conductor 32 in a hot condition which in turn will maintain the'vapor lock in the conduit 'ZTand will tend to maintain the temperature of the g'enerator absorber A without however heating thesam'e to a degree sufiicient to continue generationof refrigerant. The apparatus will remain in this condition until the supporting member 98 is raised to disengage the elements 13 and 99' at which point the element 13 will snap to its extreme right position against the stop 1'6 de-energiz'ing the auxiliary heater 41 and energizing the main burner M!" of the generator-absorber The U-shaped member 98 is raised and lowered in accordance with the refrigeration demand 'by' means of a cord mechanism actuated by the thermostat against the biasof spring 94. This mechanism comprises a bell crank lever I92 pivotally mounted at 1'03 which is connected to the members 98 by a cord "I0 1. The opposite arm of the bell 'cranklev'er is connected to the element 93 by a cord I05 passing around a guide pulley IDii. When the element 93 moves to the right, as viewed in Figure 2, "indicating a demand for refrigeration, slack is introduced into the cord I05 to permit the bell crank N12 to rotate in a counter-clockwise direction under the bias oi the torsion spring 1118 and to raise the member 98 to remove the stops 99-499 from the path of movement of the snap acting arm 13. In this condition the apparatus will cycle continuously under the control of the generator-absorber responsive thermostatic mechanism 8 l8-'I "That is the snap mechanism will shift the valve plate 99 between its extreme positions to energize the burners 49-40 alternately. When the refrigeration demand is met the thermostat 95 will collapse and the element!!! will advance to the left, as viewed in Figure 2, and tension the cord I65 to rotate the bell crank Hi2 in a clockwise direction to allow the element 98 'to drop into the path of movement of the element 1-3. When this occurs whichever part of the apparatus is then operating on a generating phase of operation will continue to do so until the generating period is completed whereupon the link 13 will be snapped over center by the thermostatic mechanism ill-8i and will come to rest in position a or d against the stop '99 or 99 respectively. This will de-energi'ze burner 41! or 41'!" and will energize the burner '41 or 41" associated with whichever generator-absorber has just completed its generating phase of operation to maintain the vapor lock and prevent a new absorbing cycle from initiating operation. At this time the other generator-absorber will have substantially completed its absorbing period of operation but it will continue to absorb such refrigerant, if any, as may remain in its associatedevaporator system. When the apparatus again demands refrigeration the element 98 will be raised in the manner above explained and will permit the snap acting arm I3 to complete its arc of movement agains tone of the stops I6 under the influence of the spring I4 which will return the apparatus to normal cycling operation without being effected by the temperature control mechanism. The apparatus is thus returned to normal cycling operation with one generator-absorber fully charged with refrigerant and one generator-absorber fully discharged to begin adsorption and production of refrigeration immediately.

The apparatus also includes a mechanism for defrosting and shut-off purposes. This mechanism is shown in Figures 2 and 3 and comprises a manually operable dial IID rotatably mounted on the front wall of the housing 81. A looking plate I I I is rigidly mounted with the dial I I8 rearwardly of the front panel of the casing 81 and movable with the dial IIlI. Also rigidly se- 7 cured to and movable with the dial I Ill is a drum II2. 'One end of a cord H3 is secured to the periphery of the'drum II2 to be wrapped around said drum when the dial I II] is rotated. The free end of the cord H3 is secured to a disk H4 to which a-pair of cords I I5 and H5 are secured. The cords H5 and II5 are anchored to the periphery of sector shaped drums H6 and IIS', respectively, pivotally carried by the control plate TI. The drums II6I I6 are integral with larger sector elements II'II H which are provided with projecting peripheral flanges respectively, extending across the plane of movement of the snap acting arm I3. In Figures 2 and 3 the dial III] is shown in the fon position of the apparatus with the arrow lying horizontally and pointing toward the left.

When the drum is rotated 90 clockwise so that the arrow points straight up a notch I20 in the disk III is rotated into engagement with a pivoted bell crank I2I pivoted on housing 81. The bell crank is biased into contact with the disk I I I by a torsion spring I22. When the notch IZEI is brought into registry with the end of the bell crank I2I it engages the same and releasably locks the drum in the defrosting position. Movement of the dial IIO to the defrosting position tensions the cords H3, H5 and H5 and rotates the sectors I I'II I'I' sufficiently to force the snap acting lever I3 into either of the dotted line positions b-c of Figure 2. That is, the sectors will move the lever I3 to a position closely adjacent its dead center position but lying on the side of the center position from which the movement of the lever started. When the arm I3 is in either of positions 12-0 of Figure 2 the port 6| will lie between the ports 65 and 61 of the chamber 56 and prevent flow of gas from that chamber through any of its exit ports. By this construction the entire apparatus is held in inoperative condition when the dial is turned to the defrosting mark.

The bell crank I2I has a forwardly projecting foot I24 which extends into the path of movement of the plate 93. As the temperature in the food cabinet warms up to a temperature such as 55 F., for example. the bellows 95 expands sufficiently to force the plate 93 to the right a distance great enough to contact the projecting foot I24 of the bell crank and rotate the same in a counterclockwise direction to release the engagement between the bell crank and the notch I 20. When this occurs the torsion springs I25I25' bias the sectors I I'I--IIl', respectively, to their inactive positions against stop I26-I26' and rotate the dial I III and its associated parts back to the position shown in Figures 2 and 3.

If the dial III) is rotated in a clockwise direction so that the arrow of Figure 2 is horizontal but pointing to the right the notch I20 is brought into position to be engaged by a spring pressed latch I 21 which engages the notch to hold the drum I I I in fixed position.

The engagement between the bell crank I21 and notch I29 as well as the engagement between the notch I 29 and the spring latch I2! is sufiicient to retain the drum H2 in fixed position against the bias of the springs I25I25, but it is insufficient to retain the drum in fixed position when the same is twisted by hand. The apparatus may be removed from defrosting condition or from the off condition by imparting a slight twisting motion to the dial to disengage the notch I20 from bell crank I 2I or the latch I27 after which the springs I25-I25' will complete movement of the dial and drum to the on position illustrated in Figure 2.

When the drum H2 is retained in the off position above explained the flanges II8-II8 retain the snap lever at I3 in position b or c in the same manner in which this element is retained in those positions for defrosting operation. The sectors Ill-II? rotate through a wider arc of movement when they operate in response to movement of the'dial IIB to the off position, however the latter half of this are of movement does not alter the position of the lever I3. During this part of the movement of the sectors the surfaces H8 or II8' as the case might be simply slide in contact with the lever I3. 7

In accordance with the present invention the control mechanism is required to'operate only small gas bleeder valves to control both the main gas supply to the system and the cooling system. This feature permits the control mechanism to be constructed of comparatively small and light weight materials and to operate with a minimum of forces.

In accordance with the present invention the operation of the apparatus is suspended at any time the demand for refrigeration is satisfied with the vapor lock maintained on the previously heated generator so that immediately a new demand for refrigeration evidences itself a fully discharged generator will beavailable to produce the refrigerating effect in conjunction with an evaporator which thenv contains a complete charge 'of refrigerant.

While I have illustrated and described the invention in considerable detail, it is to be understood that various changes may be made in the arrangement, proportion and construction of parts without departing from the spirit of the invention or the scope of the appended claims.

1. In a refrigerating apparatus of the type having a part which is alternately subjected to heating and cooling to cause operation of the apparatus, a gas burner arranged to heat said part, cooling means arranged toconduct a coolingmedium in heat exchange relation with said part, said cooling means including a heat responsive portion for interrupting flow of cooling medium to: said part when heated and. arranged to be heated when said heating means applies heat. to said heated part, an. auxiliary gas burner arranged. to heat said heat responsive portion, means: for supplying gas to said gas burners, cycling control means operating said gas supply means to supply gas? to said first mentioned gas burner intermittently to heat said part and said heat responsive portion, and. refrigeration demand responsive means for modifying the action oi said cycling control means to supply gas to said; auxiliary gas burner only to prevent cooling of said. part when refrigeration demand is satisfied.

2 In an absorption refrigerating apparatus of the: intermittent. type: which is alternately subjected to heat to generate refrigerant and cooled to produce a refrigerating eifect, means for heat ing said apparatus, means for cooling said apparatus including a heat responsive part which discontinues the cooling efiect when heated, said part being arranged to be heated simultaneously with: said apparatus, acontrol mechanism responsiye to a condition of said apparatus for activating and de-activating said heating means alternately, means. for heating said part, and refrigeration demand. responsive" means for activating: said. last mentioned heating means to prevent cooling of said apparatus and the production. of refrigeration. when the refrigeration demand is satisfied.

32. Refrigerating; apparatus. of the absorption type comprising. a pair of intermittent refrigerating: units having parts which are alternately lieatedl and; cooled in out: ofphase relation to produce. a refrigerating effect, means for heating and cooling said parts, control means for regulating the operation of said heating and cooling means including; amember normally movable between twopositions in each of which one of said parts is. heated and another of which iscooled, refrigeration demand responsive means including. a part which moves into the? path of movement-of' said" member to arrest movement thereof shorttofone of saidipositions to discontinue heating all of. said parts, and manually operated means for moving said member to a position in which" said heating means are inoperative independently of the: operation of said refrigeration demand, responsive means.

4". In a-refrigerating'apparatus of the absorption type having a cooling unit and apart which isralternately heated and cooled, a gas burner for heating saidl part, means for coolingsaid part, achamberfor receiving gas under pressure from a sourceof supply, means for conducting gas from. said chamber tosaid gas burner including a gas valve biased to closedposition, a diaphragm having oneside subjected to the pressure in said chamber" and: connected tooperatesaid valve to open-position when responding; to said pressure, a chamber? facing the other side of? said diaphragm, means: forming a-bleed' passage to permit gas under pressure to: flow into said second mentioned chamber whereby the pressure is equalized on both sides of said. diaphragm, an exhaust port for discharging gas from. said sec-- ond mentioned chamber at a rate greater than the: rate: at which gas enters said chamber through. said' bleed passage; a valve for controlling" said exhaust" portend control means for operating" said" second. mentioned: valve for con trolling: said gas burner;

In. arefrigerator; a pair of intermittent absorptiorrrefrigerating runita a pair-tot: gas burners each of which is arranged to heat one of said units, cooling means for said uni-ts including par-ts associated with each unit arrangedwhen heated to prevent cooling of the associatedunit, control means comprising a pair of gas valves biased to closed position, each ofsaid gas valves being arranged to control the flow ofgas to one of said burners, a pair of pressure responsive means each connected to operate one of said gas valves, means for subjecting each of said pressure responsive means to see under pressure in a manner tending to operate said pressure responsive means to open said gasvalves, by pass means for subjecting. said pressure responsive means to said gas under pressure in a manner tending to operate said. pressure responsive means to close said gas valves, a pair of venting means for relieving said pressure responsive means of gas under pressure tending to operate saidpressure responsive means toclose said gas valves; and cyclingeoptrol means operable to open said venting means successively to' supply gasto said gas burners successively.

6. Refrigerating apparatus including a pair of intermittent absorption refrigerating; systems of the type which are successively heated andcooled in. operation. means for heating said ysystems, means for cooling. said systems including heat responsive means arranged. to be heated simul-- taneously with said systems and operable to discontinue cooling of the systems being. heated, means for governing. the operation of saidheating and cooling means, thermostatic cycling control. means responsive to the thermal condition of portions. of said systems for operating; said governing. means to' heat and cool each of said systems successively and. inout of phase relation Witheach other,. refrigeration demand responsive means for modifyingthe operation of said cycling controlmeans when the refrigeration demand is satisfied to prevent said cycling control means from operatingv said governing meanstc heat the refrigerating system normally next tobe heated by said heating means, and means operative to heat said heat responsive means toprevent cooling of the previously heated refrigerating system when said refrigerationdemand-responsivemeans operates to modify said cycling control-means.

7-. Refrigerating. apparatus including a pair of intermittent refrigerating, systems of the type which are successively heated and cooled operation each including a heatingtmeans; a cooling means having a heat responsive part arranged to be-heated simultaneously with the system and operativewhen heated to prevent cooling of the system, and an auxiliary heatingmeansarranged to heat said heat responsivepartr control means comprising means responsive to a condition of the system for activating saidheating: means successively, refrigeration demand responsive means'formodifying the operation of saidcontrol means to deactivate both said heating means and to activate the auxiliary heating means: associated withthe previously heated-system as long asrefrigeration demand is satisfiedv 8; Refrigerating apparatusincludinga-pair of intermittent refrigerating systems of the; type which are successively heatedand cooledin operation each including a heating means; a cooling means having a heat responsivepartarranged to be heated simultaneously with the system and operative when heated to preventcooling.- of: the system, and auxiliary heating means arranged to heatsaid-heat responsive part; ocntrl means: comprising means responsive to a condition of the system for activating said heating means successively, refrigeration demand responsive means for modifying the operation of said control means to de-activate both saidheating means andto activate the auxiliary heatingmeans of the previously heated system as long as refrigeration demand is satisfied and manually operable means de-activating all of said heating means.

9. Refrigerating apparatus including a pair of intermittent refrigerating systems of the type which are successively heated and cooled in operation each includinga heating means, a cooling means having a heat responsive part arranged to be heated simultaneously with the system and operative when heated to prevent cooling of the system, and an auxiliary heating means arranged to heat said heat responsive part; control means comprising means responsive to a condition of the system for activating said heating means successively, refrigeration demand responsive means for modifying the operation of said control means to de-activate both said heating means and to activate the auxiliary heating means of the previously heated system as long as refrigeration demand is satisfied and manually operable means for modifying the operation of said control means to de-activate all of said heating means, and means operated by said refrigeration demand responsive means responding to an abnormal temperature condition for operating said manually operable means to a position in which it is ineffective to modify the operation of said control means.

10. Refrigerating apparatus comprising a pair of intermittent absorption refrigerating systems each including a generator-absorber, a condenser, and an evaporator connected in circuit; a heater associated with each of said generator-absorbers. control means for said heaters including a part movable between two control positions in each of which one of said heaters is activated to heat its associated generator-absorber,. thermostatic means responsive to the thermal condition of said generator-absorbers for operating said part between said positions to heat said generator-absorbers alternately, refrigeration control means operative in response to satisfaction of refrigeration demand to arrest movement of said part in a position in which neither of said heaters is activated, manually settable means operative to shift said part to a position in which neither of said heaters is activated, and means operated by said refrigeration control means responding to a defrosted condition of said evaporators for releasing said part from restraint by said manually settable means.

11. Refrigerating apparatus of the absorption type comprising a pair of intermittent refrigerating units having parts which are alternately heated and cooled in out of phase relation to produce a refrigerating effect, means for heating and cooling said parts, said cooling means including means associated with each of said parts and arranged to be heated therewith operative when heated to prevent cooling of its associated part, means arranged to heat each of said last mentioned means independently, control means for governing the operation of all of said heating means including a member normally movable between two positions in each of Whichone of said parts is heated and the other of said parts is cooled, refrigeration demand responsive means including an element which moves into the path of movement of said member to arrest movement thereof between said positions 'in which said control means activates whichever of said second mentioned heating means is associated with the part previously heated, and manually operated means for moving said member to another position in which all of said heating means are inactive independently of the position of said refrigeration demand responsive means.

12. A refrigerating apparatus of the absorption type having a cooling unit and a part which is alternately heated and cooled, a gas burner for heating said part, heat operated means arranged to be heated simultaneously with said part for rendering said cooling means inoperative when heated, an auxiliary gas burner for heating said heat operated means, means for cooling said part, a chamber for receiving gas under pressure from a source of supply, means for conducting gas from said chamber to said gas burner including a gas valve biased to closed position, a diaphragm having one side subjected to the pressure in said chamber and connected to operate said valve-to open position when responding to said pressure, a second chamber facing the other side of said diaphragm, means forming a bleed passage to permit gas under pressure to flow into said second chamber whereby the pressure is equalized on both sides of said diaphragm, an exhaust port for discharging gas from said second chamber at a rate greater than the rate at which gas enters said second chamber through said bleed passage, a valve for controlling said exhaust port, control means for operating said second mentioned valve for controlling said gas burner, and means operable to supply gas to said auxiliary gas burner through said second mentioned valve when it is in a position to close said port.

13. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems each including a part which is successively heated and cooled in operation, means for heating and. cooling said parts, means for governing the operation of said heating and'cooling means, thermostatic cycling control means responsive to the thermal condition of said parts of said systems for operating said governing means to heat and cool each of said parts successively and in out of phase relation with each other, refrigeration demand responsive means operative when refrigeration demand is satisfied to bar operation of said governing means by said cycling control means to apply heat to whichever of said parts is being cooled when refrigeration demand is satisfied, and manually operable means for operating said governing means to terminate heating and cooling of said parts independently of the action of said refrigeration demand responsive means and said cycling control means.

14. Refrigerating apparatus including a pair of intermittent absorption refrigerating systems each including a part which is successively heated and cooled in operation, means for heating and cooling said parts, means for governing the operation of said heating and cooling means, thermostatic cycling control means responsive to the thermal condition of said parts of said systems for operating said governing means to heat and cool each of said parts successively and in out of phase relation with each other, refrigeration demand responsive means operative when refrigeration demand is satisfied to bar operation of said governing means by said cycling control means to apply heat to whichever of said parts is being cooled when refrigeration demand is satisfied, manually actuated means movable from an inoperative position to an operative position for operating said governing means to terminate heating of said both of said parts independently of the action of said refrigeration demand control means and said cycling control means, means biasing said manually actuated means to said inoperative position, releasable means for retaining said manually actuated means in said operative position and means operated by said refrigeration demand responsive means for releasing said releasable means when said responsive means responds to a defrosting temperature condition.

GEO. A. BRACE.

REFERENCES CITED The following references are of record in the file of this patent:

Number 15 Number 14 UNITED STATES PATENTS Name Date Kerr, Jr. et al. Jan. 2, 1934 Hulse June 11, 1935 Hainsworth Nov. 26. 1935 Normelli Aug. 11, 1936 Andersson July 19, 1938 Buchanan Oct. 25, 1938 Af Kleen July 18, 1944 Coons June 26, 1945 Gross Oct. 29, 1946 Coons June 19, 1951 FOREIGN PATENTS Country Date Australia May 25, 1943 

